The invention provides a sealing ring which may be used either as a shaft seal or a piston ring in which the joint formed by the split ends of the ring provides no axial passage and no radial passage for fluids at the split other than a very small opening at the extreme center of the ring due to the engagement between nesting surfaces which are inclined to the axis of the ring and do not intersect the inner circumferential face of the ring.
Rings have long been used to seal the clearance opening provided between a rod, shaft or a piston and its surrounding cylinder wall where a clearance, even though small, must be provided to prevent binding when one of the parts is moved relative to the other. In order to install such a ring in its ring groove, it is necessary that the ring be expanded to pass over the shaft, rod or piston on which it is to be installed. To do this, the inner diameter of the ring must be expanded which requires the ring to be split at one point. Thus, there is created the necessity of a joint. Many different constructions have been developed in the past to minimize leakage past the ring at the joint. Many of the joints, in addition, are designed to provide a lock which will detachably secure the ends of the ring together after the rings have been seated in their appropriate grooves. How the latch by which the ends of the ring are connected is designed will, in part, depend upon the use to which the ring is intended to be applied.
In almost all ring applications, one of the more difficult problems to solve is that of reducing and, to the extent possible, eliminating leakage past the ring through the gap or gaps at the joint which result from the fact that it is, as a practical matter, not possible to bring the ends of the closed ring into tight circumferential abutment due to the fact that the ring must provide a certain amount of circumferential adjustment at the splice to accommodate normal manufacturing tolerances. Further, the rings, in most circumstances, must operate through a wide temperature range which results in expansion and contraction of the ring. The necessity of allowing for thermal expansion and accommodating unavoidable tolerance variations makes the problem of controlling leakage at the ring joint or splice difficult. To effect this, many rings have been designed with the objective of making the passage for fluids at the ring joint as tortuous and indirect as possible. This procedure is complicated by the fact that in rings of the type with which this invention is concerned must provide a joint which will latch the ends together once the ring has been closed. There is also the problem of providing precisely shaped and sized surfaces which will mate with a minimum gap due to tolerance accumulation. A further limitation is that many shapes which could be devised for this purpose at the ring gap cannot be machined, cast or otherwise formed by practical means. Examples of latch structures which are difficult to manufacture and yet fail to provide essential operating characteristics are to be found in patents such as U.S. Pat. No. 2,080,935, issued May 18, 1937 to S.S. Slyk and U.S. Pat. No. 4,533,149, issued Aug. 6, 1985 to G.R. Vader. These are merely exemplary.